The present invention relates to novel 3-nitroisoxazoles, a process for their preparation and to the use of novel and known 3-nitroisoxazoles as biocides for protecting industrial materials.
Some 3-nitroisoxazoles having alkyl, aryl, hetaryl, alkinyl and alkoxycarbonyl radicals are known; a biological action of the compounds mentioned has not been described. (K. Baum. J. Org. Chem. 1985, 50, 2736; K. Kim, Tetrahedron Lett. 1996, 37, 7791; K. Eiter, Naturwissen-schaften 1972, 59, 468; E. Duranti, Tetrahedron Lett. 1973, 7, 485).
3,5-Dinitroisoxazoles are known; here, too, an antibacterial action has not been described (D. T. Corner, Acta Crystallogr., Sect. C. Cryst. Struct. Commun. 1987, 43, 2011). Specifically substituted 3-nitroisoxazole-5-carboxaldehyde derivatives are known and in some cases have weak to moderate antibacterial actions (E. Duranti II Farmaco Ed. Sc. 1987, 42, 299).
The invention relates to a method comprising treating a microbe or a habitat of the microbe with a compound of the formula (I) 
wherein R1 and R2 independently of one another each represent hydrogen, halogen, nitro, cyano, or represent in each case an optionally substituted alkyl, alkenyl, alkinyl or aryl, such that the compound is allowed act on the microbe or its habitat.
In one embodiment, Applicants"" invention is directed to a microbicidal composition comprising: (A)a compound of the formula (I) 
wherein R1 and R2 independently of one another each represent hydrogen, halogen, nitro, cyano, or represent in each case an optionally substituted alkyl, alkenyl, alkinyl or aryl, (B) solvents or diluents and, (C) optionally processing auxiliaries, or active compounds, or mixtures thereof.
In one embodiment, Applicants"" invention relates to a process for preparing a compound of the formula (I) 
wherein R1 and R2 independently of one another each represent hydrogen, halogen, nitro, cyano, or represent in each case an optionally substituted alkyl, alkenyl, alkinyl or aryl,
in which the process comprising reacting (i) a compound of the formula (II)
R2xe2x80x94Cxe2x89xa1Cxe2x80x94R1xe2x80x83xe2x80x83(II)
wherein R1 and R2 are each as defined above with (ii) tetranitroethylene, and optionally in the presence of a diluent.
In another embodiment, Applicants"" invention relates to a process for preparing a compound of the formula (I) 
wherein R1 is hydrogen, halogen, nitro, cyano, or represent in each case an optionally substituted alkyl, alkenyl, alkinyl or aryl, R2 represents hydrogen. In this embodiment, the process comprises reacting (i) a compound of the general formula (III)
Xxe2x80x94CH2xe2x80x94Cxe2x89xa1Cxe2x80x94R1xe2x80x83xe2x80x83(III)
in which R1 is as defined above and X represents a leaving group, preferably bromine, iodine, chlorine, tosylate or mesylate with (ii) metal nitrites, optionally, in the presence of diluents. These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims.